The investigation outlined in this proposal has as its objective the isolation and structure determination of the tumor-inhibitory alkaloidal constituents of eight selected plants. These plants, which are members of the families Menispermaceae, Lauraceae, Ranunculaceae and Apocynaceae, have yielded alkaloidal fractions in our laboratory which have been shown to have confirmed activity by NCI (B002 in the KB nasal pharynx cell system).